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Lm l H l I I I I I c-r-o' e Au. muffin I e |c a S- 4: o-o lo-o 9540 mi I L5* man Ale@ l United States Patent 3,153,437 STOGE CNVEYR SYSTEM Earl E. Hoellen, Hales Corners, Wis., assigner to Cutler- Harnrner, Inc., Milwaukee, Wis., a corporation of Delaware Original application Aug. 31B, 1960, Ser. No. 52,846, now Patent No'. 3,118,549, dated Jian'. 21, 1964.- Divided and this application Mar. 20,1963, Ser. No. 266,650

Claims. (Cl. 214-46) This invention relates to storage conveyor systems and more particularly to` systems for selectively controlling withdrawal of articles from selected storage conveyors in a desired order.

While not limited thereto, the invention is especially applicable to conveyor systems having a buffer storage area for storage of automobile bodies or the like awaiting conveyance thereof into a production line.

An object of the invention is to provide an improved conveyor system.

Another object of the invention is to provide an improved storage conveyor control system for controlling withdrawal of articles from selected storage conveyors onto an outgoing conveyor in a sequence such that the articles are arranged in succession on the outgoing conveyor in the selected order and are thereby conveyed to an assembly line whereby the storage conveyors provide a collection area aording a supply of a given type or types of articles for selective withdrawal to maintain Voperation of the assembly line during times when other types of articles cannot be utilized therein.

A more specific object of the invention is to provide an improved conveyor control system for controlling selective withdrawal of articles from a plurality of storage conveyors.`

Another specific object of the invention is to provide an improved conveyor control system for controlling selective withdrawal of articles from a plurality of storage conveyors onto an outgoing conveyor in a sequence such that the articles are arranged in succession on the outgoing conveyor in accordance with the selection.

EAS? Patented Oct. 20, 1964 and is also operable to control a plurality of article stops at various points in the conveyor system to control the movement of the articles. Also, such control system is transferable between automatic and manual control to afford flexibility in its operation.

This application relates to the exit portion of the aforementioned storage conveyor system including a control system therefor whereby articles may be selectively withdrawn from the storage conveyors in a desired order and conveyed to an outgoing conveyor. For a disclosure of the entry portion of the storage conveyor system affording selective control of conveyance of articles onto the storage conveyors, reference may be had to the aforementioned patent.

The aforementioned and other objects and advantages of the invention and the manner of obtaining them will best be understood by reference to the following detailed 'description of an exemplary embodiment of a storage conveyor system and control system therefor taken in conjunction with the accompanying drawings, wherein:

FIGURE l is a schematic illustration of a conveyor system layout constructed in accordance with the invention;

A further object of the invention is to provide an improved conveyor control system for controlling withdrawal of an article from each of a plurality of storage conveyors concurrently onto an outgoing conveyor.

A related object of the invention is to provide in such control system selectable automatic Vand manual control means for controlling the aforementioned functions.

This application is a division of copending application Serial No. 52,846, tiled August 30, 1960, now Patent No. 3,118,549 dated January 2l, 1964. According to such patent, there is provided a storage conveyor system having an incoming conveyor for conveying articles in succession toward a storage area, an accumulator conveyor for accumulating a predetermined number of articles from the incoming conveyor awaiting storage, an entry shuttle conveyor having access from Ithe accumulator conveyor and operable to travel past the entry ends of a plurality of storage conveyors for conveying articles to the latter in a selected order, an exit shuttle conveyor operable to travel past the exit ends of the storage conveyors for receiving articles from the latter, an outgoing conveyor having access from the exit shuttle conveyor for conveying withdrawn articles to an assembly line, and appropriate transfer rams or transfer conveyors for effecting transfer of the articles between the aforemention-ed conveyors. A control system is provided for controlling admission to and withdrawal of articles from the storage conveyors, such control system being under the control of a plurality of entry and exit control pushbuttons and limit switches. Such control system is operable to control the aforementioned conveyors or transfer rams FIG. 2 is an illustration of a main operators station and control devices thereon;

FIG. 3 is an illustration of an eXit manual operators stationand control devices thereon; and

FIGS. 4 through l2 diagrammatically show the control circuits for controlling the conveyor system of FIG. 1; FIGS. 4 through 12 showing various conveyor motor control circuits and circuits for controlling the exit cycle, that is, the withdrawal of articles from storage.

Referring to FIG. 1, there is shown a storage conveyor system layout having a main operators station provided with a control panel 2 for` controlling entry or storage of articles and exit or withdrawal of articles and an exit operators station having a control panel 4 for controlling exit or withdrawal of articles from storage under manual controls.

The entry portion of the conveyor system comprises an incoming conveyor 6 for conveying articles toward the storage area. Incoming conveyor 6 has direct access to a No. 1 accumulator conveyor 8 wher-con a predetermined number of articles are accumulated and temporarily stored awaiting movement thereof to the storage conveyors. Accumulator conveyor 3 in turn has direct access to a ram type loader transfer conveyor 10 for successively transferring articles from accumulator conveyor 8 onto an entry shuttle conveyor 12. A plurality of storage conveyors Nos. l, 2, l0 and L are equally spaced along shuttle conveyor 12 and arranged transversely v relative to the latter and a corresponding plurality of entry transfer-in conveyors 14, 16, 18 and 20 are arranged between shuttle conveyor 12 and the respective storage conveyors for transferring articles from the shuttle conveyor onto the respective storage conveyors. While four storage conveyors have been shown for ease of illustration, it will be apparent that any desired number thereof can be provided, L being indicative of the total number of and the last storage conveyor.

The exit portion of the conveyor system comprises the aforementioned storage conveyors and a plurality of ram type exit transfer-out conveyors 22, 24, 26 and 28 arranged between the exit ends of the respective storage conveyors Nos. l, 2, 10 and L and an exit shuttle conveyor 30, these transfer-out conveyors being equally spaced along and having access to the exit shuttle conveyor. The latter has direct access to an unload transfer-off conveyor 32 for transferring articles from exit shuttle convey-or 30 to a No. 2 accumulator conveyor 34. Accumulator conveyor 34 is provided for transferring articles from unload transfer-olf conveyor 32 fa la? to intermediate conveyor 36 which conveys the articles away from the storage area. At the exit end of intermediate conveyor 36, there is provided another No. 3 accumulator conveyor 38 which functions to gather the articles, that is, to eliminate any gaps therebetween before such articles enter upon an outgoing conveyor 4&3.

All of the conveyors shown in FIG. 1 and pertaining to this invention are adapted for supporting and moving therealong four-wheeled trucks which support the articles being conveyed such `as autobodies or the like. Storage conveyors Nos. 1, 2, and L and exit transferout conveyors 22, 24, 26 and 28 move the article supporting trucks in the forward direction.V Exit shuttle conveyor 3l) moves the trucks sideways in the right-hand direction in FIG. l. Unload transfer-olf conveyor 32. No. 2 accumulator conveyor 34, intermediate conveyor 36, No. 3 accumulator conveyor 3S and outgoing conveyor du move the trucks in the reverse direction. Therefore, if the articles `are positioned on the trucks in storage in the reverse direction, they will come out on the outgoing conveyor in the forward direction, the conveyor system effecting turning of the trucks 18() degrees.

Unlo'ad transfer olf conveyor 32, intermediate conveyor 36 and outgoingrconveyor 4t) are preferably of similar type. In accordance with the detailed description of operation of the conveyor control system hereinafter appearing, each of these conveyors is disclosed as being of a type which positively moves the truck when the conveyor is running and stops moving the truck when the conveyor is stopped. While conveyors for doing this may take various forms, for exemplary purposes, each of these conveyors is preferably provided with a roadway comprising a pair of spaced, parallel tracks along which the trucks may be rolled and a motor-driven device for pushing the trucks along the tracks. This device may be an endless chain moved by motor-driven sprockets and having one or more projections or dogs thereon. The dogs are mounted on the chains for engaging the undercarriage of the trucks, to push the same along the tracks. Unload transfer off conveyor 32 may be provided with a single dog on the chain thereof so that when this conveyor is Astarted running, such dog hooks the undercarriage at the rear end of the truck and pulls it off the extreme right-hand end of the exit shuttle conveyor and pushes it ontoY No. 2 accumulator conveyor 34. Intermediate conveyor 36 is preferably provided with a plurality of ldogs spaced apart on its chain. Each time a truck reaches the idle point hereinafter described adjacent the entry end of the intermediate conveyor, the next dog on the chain hooks this truck and pushes it along the intermediate conveyor. This conveyor 36 normally runs continuously except that it is stopped whenever No. 3 accumulator conveyor 38 is full as hereinafter described. Outgoing conveyor 40 is preferably like the intermediate conveyor and is provided with a plurality of dogs on its chain, these dogs being spaced apart in accordance with the lengths of the trucks as desired. So long as No. 3 accumulator conveyor 38 is not empty, each successive dog on the outgoing conveyor pusher chain will hook a truck and move the trucks in equally spaced relation to the assembly line. As will be apparent, the purpose of the No. 3 accumulator conveyor is to maintain a constant supply of article trucks at the entry end of the outgoing conveyor whereby to gather the articles and eliminate any yspaces therebetween.

Storage conveyors Nos. l, 2, 14 and L, No. 2 accumulatorconveyor 34 and No. 3 accumulator conveyor 38 are preferably of similar type except that conveyor 34 is not provided with an article stop and is additionally provided with an idle or inactive portion at the exit end thereof. In accordance with the detailed description of operation of the control system hereinafter appearing, each of these conveyors is disclosed as being of the type which runs continuously and conveys the trucks therealong. Since these conveyors with the exception of No. 2 accumulator conveyor arek each provided with an article stop hereinafter described, provision is made for permitting these conveyors to continue running after the article is stationary against the stop. While conveyors for doing this may take various forms, for exemplary purposes, each of these conveyors is provided with a pair of spaced apart, motor driven chain-type conveyor belts. The respective pairs of side Wheels of the trucks are supported by the belts of such pair thereof and the moving belts convey the truck along each such conveyor. When the truck engages the stop on those conveyors having such stop, the belts continue to move and turn the truck Wheels but the truck remains stationary against the stop. No. 2 accumulator conveyor 34 similarly conveys a truck therealong to the idle portion thereof immediately adjacent the entry end of the intermediate conveyor. This idle roll portion or transfer portion permits free entry of a truck conveyed thereto by the accumulator conveyor belts but does not move the trucks therefrom. Thus, each truck will idle or rest on this portion of the conveyor Whenever the intermediate conveyor is stopped and until it is pulled therefrom by a dog on the intermediate conveyor chain when the intermediate conveyor is restarted.

Exit transfer out conveyors 22, 24, 26 and 28 are preferably of Vsimilar type. In accordance with the description of operation of the control system hereinafter appearing, each of these conveyors is disclosed as being of a type which positively pushes a truck arriving thereon all the way onto the associated shnttel conveyor. While conveyors for doing this may take various forms, for exemplary purposes, each of these conveyors is preferably provided with a pair of spaced apart and parallel roadway tracks on which the truck rolls and a ram or the like for pushing the truck therealong and olf and beyond the exit end 'thereof onto the associated exit shuttle conveyor.

Exit shuttle conveyor 30 is preferably adapted for supporting and conveying the article supporting trucks sideways, that is, in the right-hand direction according to FIG. 1. This shuttle conveyor must also be capable of having trucks rolled theeron when pushed by the exit transfer out rams. While conveyors for this purpose may take various forms, for exemplary purposes, the exit shuttle conveyor is preferably a Slat-type conveyor having a series of slats or flats pivotally connected to one another in series in an endless chain. In this manner, the slats provide a flat surface onto which a truck can be rolled and the 'conveyor is sectionalized so that -it can move around the turns at veach end when driven by an electric motor.

All of the aforementioned conveyors are of known types and the Vdetails thereof have not been shown to avoid complicating the drawings. While only four storage conveyors have been shown in FIG. 1, any desired number of additional storage conveyors could similarly be arranged between vstorage conveyors Nos. 2 and 10.

The conveyors 'of FIG. 1 are also provided with a plurality of limit switches for controlling operation of the system. These limit switches are mounted on the conveyors in the positions shown in FIG. 1 so as to be voperated in their proper order. Certain of these limit switches'are operated by a portion of the undercarriage of the article supporting trucks as the latter pass thereover and others of these limit switches are operated by the struction and the details thereof have not been shown to avoid complicating the drawings.

Exit shuttle conveyor 30 is provided at its right-hand end with a limit stop control device LSCZ for stopping the shuttle conveyor if the article should travel beyond its normal stopping position. Limit stop control device LSCZ is provided with a Ilight source P'CLZ and a photocell PC2 for detecting an overshoot condition of the article as more fully hereinafter described'.

Referring to FIGS. 2 and 3, there are shown a main operators station control panel 2 and an exit manual operators station control panel 4 which are also shown schematically in FIG. l. These control panels have mounted thereon a plurality of pushbutton and selector devices which are manually controllable by the main and exit operators for causing the system to perform the various control functions hereinafter described.

Control panel 2 is provided with a start switch PS2 and a stop switch SSZ for controlling accumulator conveyor 34 identified also as No. 2 and a start switch PS3 and a stop switch SSS for controlling accumulator conveyor 3S identified also as No. 3. A start switch PSS and a stop switch SSS are provided for controlling intermediate conveyor 36. A start switch PS6 and a stop switch SSG are provided for controlling the storage conveyors Nos. l, 2, 10 and L in unison. An add switch PSM and a subtract switch P815 are provided for manually operating or positioning the counter of accumulator conveyor No. 3. Add switches PSM, P817, PSIS and PSM? are provided for manually operating or positioning the counters of storage conveyors Nos. l, 2, 10 and L, respectively. A selective manual-auto rotary switch RS is provided for transferring the system between manual and automatic operation. A plurality of two-button stopreset switches SRI, SR2, SRM) and SRL are provided for selectively controlling stopping and starting of the respective storage conveyors Nos. l, 2, l0 and L, respectively.

At the lower portion of control panel 2 there are provided a plurality of additional control devices for controlling the exit cycle portion of the system, that is for controlling withdrawal of articles from the storage conveyors. An exit cycle start switch PS27 and an exit cycle stop switch SS2'7 are provided for controlling the exit cycle, that is, for conditioning the system so that withdrawal of articles from the storage conveyors can be selectively initiated. Another start switch P828 and another stop switch SSZS are provided on exit manual operators station control panel 4 in FIG. 3 for performing the same functions under manual control as switches PS27 and SS2'7 are capable of performing under automatic control. A single-all selective rotary switch SA is providedV at the lower portion of panel 2 for transferring the system from a condition wherein an article can be withdrawn from a single storage conveyor at a time to a condition wherein one article can be withdrawn from all the storage conveyors at once. Switches P829 and PSS are provided on panels 2 and 4, respectively, for manually Vcontrolling indexing or movement of exit shuttle conveyor 30 from the two locations. A cancel switch PSSl is provided on panel 2 for controlling cancellation after an exit selection has been made. Exit select switches PS32, P533, P5334 and PSSS are provided for making exit selections, that is, for initiating withdrawal of articles from storage conveyors Nos. l, 2, l0 and L, respectively. Subtract switches P836, PS37, PS3S and P839 are provided for operating or positioning the counters of the respective storage conveyors. An all transfer switch PS4@ is provided for controlling the transfer of articles from all the storage conveyors onto the exit shuttle conveyor. A No. l start switch PSM, a No. 2 start switch P842, a No. l0 start switch P843 and a No. L start switch PS44 are provided for manually controlling exit transfer-out conveyors 22, 24, 26 and 2S, respectively, and the release of articles from the respective storage conveyors. An unload start switch PS4S is provided for controlling unload transfer-olf conveyor 32 manually whenever an article is at the exit end of exit shuttle conveyor Sil. The circuit connections for the aforementioned pushbutton and selector switches are shown in FIGS. 4 through l2.

The control circuits for the exit portion of the storage conveyor system of FIG. l are shown in FIGS. 4 through l2. Power supply lines L1, L2 and L3 are connectable to a three-phase power supplyl source. Lines L1 and L2 are connected through a voltage reducing transformer PT in FIG, 2 4to conductors L4 and LS. There are shown in FIG. 5, motors M02 and M03 for driving accumulator conveyors 34 and 38, respectively. Motor M02 is provided with a start switch PS2 and a stop switch S82 for controlling a main power contactor ZAM whereby the motor is connected to power supply lines L1, L2 and L3. Likewise, motor M03 is provided with a start switch PS3 and a stop switch SSS for controlling a main power contactor SAM whereby the motor is connected to power supply lines L1, L2 and L3.

An electric motor MGS shown in FIG. 4, is provided for driving intermediate conveyor 36. Motor MO5 is provided with a start switch PS5 and a stop switch SSS for controlling an intermediate conveyor control relay lCR which in turn controls main contactor IM whereby `the motor is connected to power supply lines L1, L2 and L3. An add-subtract counter CTR2 in FIG. 4 is provided for counting the number of articles entering and leaving accumulator conveyor 38. Counter CTR2 is provided with an add coil A for stepping the counter in the clockwise direction one step for each article entering accumulator conveyor 38 and a subtract coil S for stepping the counter in the counterclockwise direction one step for each article leaving accumulator conveyor 38. Counter CTR 2 is also provided with switches a, b and c for performing control functions hereinafter described. A control relay lLRl having a closing coil C and a tripping coil T and a plurality'of contacts is provided for stopping intermediate conveyor 36 when a predetermined number of articles have been accumulated on accumulator conveyor 3S and for restarting the intermediate conveyor when an article is removed from accumulator conveyor 3S. Storage conveyors Nos. l, 2, 10 and L are provided with driving motors M06, M07, MOS and M09, respectively, shown in FIGS. 4 and 5. Motor M06 is provided with a stop-reset switch SR1 for controlling its main power contactor ISM whereby the motor is connected to power supply lines L1, L2 and L3. Similarly, motor M07 is provided with a stop-reset switch SR2 for controlling its main power contactor ZSM whereby the motor is connected to power supply lines L1, L2 and L3. Similarly, motor M08 is provided with a stopreset switch SR1@ for controlling its main power contactor 10SM whereby the motor is connected to power supply lines L, L2 and L3. Likewise, motor M09 in FIG. 5 is provided with a stop-reset switch SRL for controlling its main power contactor LSM whereby the motor is connected to power supply lines L1, L2 and L3. There are also provided a master start switch PS6 and a master stop switch S86 in FIG. 4 for controlling the aforementioned storage conveyor motors in unison. A storage conveyor control relay SCCR under the control of the aforementioned master start and stop switches in FlG. 4 is provided for controlling the supply of power to main contactors ISM, ZSM, 4lilSM and LSM.

Counters CR3, CTR4, CTRS and CTR6, in FIG. 5, may be operated to count and maintain a registration of the number of articles on the respective storage conveyors. Each such counter is provided with an add coil A and a subtract coil S for stepping the counter in reverse directions. These counters are also provided with respective self-operated switches EIC, E2C, E10C and ELC for preventing operation thereof when the storage conveyors are full. These counters are further provided with respective switches XIC, XZLC, XIC and XLC shown in FIGS. 7 and 8 for controlling the exit select circuits as hereinafter described. A manual-auto rotary switch RS is provided in FIG. 5 for controlling either an automatic control relay ACR or a manual control relay MCR.

In FIG. 4 limit switch lLSl controls stopping of intermediate conveyor 36 when a predetermined number of articles have been accumulated on accumulator conveyor 3S. Limit switch ILSZ controls add coil A of counter CTRZ to count the number of articles entering accumulator conveyor 38. Limit switch ILS3 controls restarting of intermediate conveyor 36 each time an article is removed from accumulator conveyor 38.

In FIG. 4 there are provided an add switch PSI@ and a subtract switch P515 for stepping counter CTRZ in reverse directions if it should get out of step with the number of articles actually on accumulator conveyor 38. In FIG. 5, there are provided add switches P816, PSI7, PSIS and P819 for manually controlling the stepping of counters CTR3, CTR-"i, CTRS and CTR@ of the respective storage conveyors in the clockwise add direction in the event they should get out of step with the number of articles actually on the storage conveyors.

In FIG. 6, there is shown a motor MOI@ having high speed winding HSW and low speed Winding LSW for operating exit shuttle conveyor 30. A high speed main contactor XSH is provided for connecting windings HSW through lines LI, L2 and L3 to the three-phase power supply source. A low speed main contactor XSL is provided for connecting windings LSW to the power supply lines. A dynamic braking circuit for motor M016 extends from lines L3 and L2 through a transformer PT4 to the input terminals of a full-Wave rectifier bridge RBZ and then from the positive and negative output terminals of bridge RBZ through contacts of a dynamic braking control contactor XSDB to low speed windings LSW.

Limit stop control device LSC2, FIGS. l and 6, is supplied from conductors L4 and L5 through a voltage reducing transformer PTS. Device LSCZ comprises a unidirectional conducting device such as a diode DRZ, a solid element semi-conductor device such as a transistor TR2, a relay XPC, resistors R3 and R4, a photocell PC2 and a light source such as a lamp PCLZ connected in a manner which will become apparent from the description of operation thereof hereinafter appearing. An exit cycle start relay XCSR under the control of start switches P527 and PSZS stop switches S827 and SSZS is provided for conditioning the system so that an exit selection can be made. An exit shuttle timing relay XSTR is provided for controlling dynamic braking contactor XSDB.

In FIG. 7, a latching relay XSDLR is provided for transferring motor M016 from high speed to low speed. A control relay XJCR under the control of pushbutton switches P829 and PS3@ affords manual control of indexing the exit shuttle conveyor, that is, movement of the exit shuttle conveyor one space at a time. Such one space of movement of the exit shuttle conveyor is defined as a distance required to move an article from a point directly opposite one storage conveyor to a point directly opposite the next storage conveyor. A relay XSLSA under the control of exit shuttle operated limit switch XSLS is provided for controlling stopping of the exit shuttle conveyor. A latching relay XSLR and relays XSCR and XSLRA are provided for controlling the exit shuttle conveyor in the event it overrides a stopping position. A relay H is provided for energizing conductor L12 in conjunction with relay XSLSA. A latching relay XLR and a relay XLRA are provided for performing various control functions hereinafter described when the exit shuttle is started. A timing relay XI-ITR is provided for initiating the operation of drive motor DMZ of exit memory device XMD, and for insuring that device XMD is set before the select relay is tripped. At the lower portion of FIG. 7 and the upper portion of FIG. 8,` there are shown a plurality of eXit select control relays XILR, XZLR, XItlLR and XLLR under the control of exit select yswitches PSSZ, P333, P834 and P835, respectively. Counter switches XIC, XZC, YXIC and XLC shown in FIGS. 7 and 8 are operable by counters CTR3, CTRfi,

CTRS and CTRo, respectively, to lock out the exit select circuits when the respective storage conveyors are empty. In FIGS. 7 and 8, subtract pushbutton switches P836, P837, P538 and P839 are connected through the conductors extendingalong the right-hand sides of FIGS. 5 through 8 to subtract coils S of counters CTRS, CTR4, CTRS and CTR, respectively, to afford manual control of operation of these counters in the counter-clockwise direction.

In FIG. 8, an exit cycle cancel relay XCCR under the control of exit cancel switch P831, the other contact of this switch being shown in FIG. 7, is provided for canceling an exit selection that has been made and being effective only during the time when a previously selected article is being transferred onto the exit shuttle conveyor. Exit memory device XMD is provided with a plurality of stationary solenoids IS, 2S, 10S and LS, one for each storage conveyor, having actuators for engaging pins P of actuator blocks AB to pivot or set the latter into their operating positions when the memory device starts to rotate. A plurality of limit switches XILS, XZLS, XILS and XLLS, one for each storage conveyor, are mounted on stationary supports around the rotary drum which carries the actuator blocks. These limit switches are arranged in the vertical columns and horizontal rows so that a limit switch corresponding to to a given storage conveyor is operable by an actuator block whenever a reserved space on the exit shuttle conveyor reaches a point directly opposite such storage conveyor as hereinafter more fully described. A resetting bar RBZ is provided just ahead of the vertical column of solenoids to reset the actuator blocks in their normal positions. Exit memory device XMD is provided with a number of columns of actuator blocks AB equal to the number of storage conveyors plus 1 for reasons hereinafter described.

top ST3 in the lower portion of FIG. 8 is provided with an up solenoid UP3 and a down solenoid DN3 for controlling raising and lowering of the stop on storage conveyor No. l.

In FIG. 9, in addition to the stop shown in FIG. 8, storage line No. l is provided with latching relays XILRI, XILRZ and X1LR3, control relays ILSIUA, XICRI and XICR and a main contactor XIM for controlling motor M017 of exit transfer-out conveyor 22. A limit switch ILSS is provided for causing stop ST3 to be raised when an article approaches the latter. Limit switch 1LS7 indicates the presence of an article against stop ST3 on storage conveyor No. l to permit lowering of stop ST3. Limit switch 1LS6 is operated by stop ST3 to permit starting of exit transfer-out conveyor 22 when the stop is lowered. Limit switch ILSS maintains operation of exit transfer-out conveyor 22 until it has completed its cycle of operation. Limit switch 1LS9Yhaving another contact at the lower left-hand portion of FIG. 7 controls subtract coil S of counter CTRS and performs additional control functions hereinafter described. Limit switch lLSlt) prevents restarting of eXit transfer-out conveyor 22 until exit shuttle conveyor 30 has removed the released from the position adjacent storage conveyor No. 1.

In the lower portion of FIG. 9 and the upper portion of FIG. 10, there -is shown a control circuit for stop ST4 and exit transfer-out conveyor 24 of storage line No. 2. Similar to that hereinbefore described in connection with storage line No. l. This control circuit includes stop ST4 and its up solenoid UP4 and down solenoid DN4, latching relays XZLRI, XZLRZ, and X2LR3, control relays ZLSIGA, XZCR and XZCRI and main contactor XZM for controlling motor M018 of exit transfer-out conveyor 24. Limit switches ZLSS, 2LS6, 2LS7, ZLSS, ZLS9 and ZLSMB are provided for performing functions like those described in connection with the limit switches having like suix numbers in storage line No. l.

In the lower portion of FIG. l0, there is shown a control circuit for stop ST5 and exit transfer-out conveyor Z6 of storage line No. l0 similar to that hereinbefore described. This control circuit includes stop ST and its up solenoid UPS and down solenoid DNS, latching relays XILRI, XIIILRZ and XItILRS, control relays ILSIA, XIilCR and XIGCRI and main contactor XIGM for controlling motor M019 of exit transfer-out conveyor 26. Limit switches ILSS, IuLSt, ItlLS, ILSS, ltiLSQ, and ItiLSItl are provided for performing functions like those described in connection with the limit switches having like suffix numbers in storage lines Nos. 1 and 2.

In FIG. l1, there is shown a control circuit for stop ST6 and exit transfer-out conveyor 28 of storage line No. L similar to those hereinbefore described. This control circuit includes stop ST6 and its up solenoid UF6 and down solenoid DN, latching relays XLLRI, XLLRZ, and XLLR3, control relays LLSIA, XLCR and XLCRI and main contactor XLM for controlling motor M02@ of exit transfer out conveyor 28. Limit switches LLSS, LLS6, LLS7, LLSS, LLS9 and LLSIiI are provided for performing functions like those described in connection with the limit switches having like suffix numbers in storage lines Nos. 1, 2 and 10.

At the lower portion of FIG. 11 and the upper portion of FIG. 12, there is shown an all transfer control circuit for controlling transfer of an article from each storage conveyor onto the exit shuttle conveyor at the same time. This circuit includes a counter CTR7 for counting the movements of the exit shuttle conveyor, latching relays ALRI and ALRZ and a control relay AICR.

The lower portion of FIG. l2 shows a control circuit for controlling unload transfer-oir" conveyor 32 when limit switch ULS2 detects the presence of an article at the right-hand end of exit shuttle conveyor 36 at least one space beyond exit transfer-out conveyor 22. This circuit includes latching relays ULRI, ULR2 and ULRS, a control relay UCR and main Contactor UM for controlling motor MOZI of unload transfer-olf conveyor 32. Limit switch ULSI maintains operation of motor M021 until the unload transfer-off conveyor has completed its cycle of operation. Limit switches ULSS, ULS4 and ULSS perform control functions hereinafter described.

The operation of the system to effect selective withdrawal of articles from the storage conveyors will now be described. The control circuits which perform these functions are shown in FIGS. 4 through l2.

Referring to FIG. 4, let it be assumed that a source of three-phase electrical power is connected to power supply lines LI, L2 and L3 in the upper left-hand portion of FIG. 4. To condition the system for starting, it may be assumed that relays XILRI, XZLRI, XItBLRI and XLLRI in the exit control portion of the system in FIGS. 9, and 11 are in their closed condition wherein contacts b, d and e of each such relay are closed and contacts a and c of each such relay are open as shown. Let it further be assumed that relays XILR3, XZLRS, XIGLRS and XLLRS in the eXit control portion of the system in FIGS. 9, 10 and 11 are in their closed condition wherein contacts b, c and d of each such relay are closed and contacts a and e of each such relay are open, contacts d and e of these relays being shown at the upper portion of FIG. l2.

In the following description, certain contacts of the relays which contacts are not shown connected by broken lines to the relay windings are identified by the associated relay reference character such as ACR in the middle of FIG. 6 and also by the contact reference character such as g.

When power is applied to supply lines LI, L2 and L3, voltage reducing transformer PTI in FIG. 5 is energized to supply power therethrough to conductors L4 and LS. As a result, relay XSLSA in FIG. 7 is energized. The circuit for relay XSLSA extends through contact b of limit switch XSLS across conductors L4 and L5. Relay XSISA closes contacts a, b, c, d and f in FIGS. 6 and 7 and opens contacts e and g thereof in FIGS. 7 and 8.

, is Automatic Operation For automatic operation of the system, the MAN- AUTO selector switch RS in FIG. 5 is turned to its AUTO operating position to close contact a and open contact b. This causes energization of relay ACR across conductors L4 and L5 in FIG. 5 and closure of contact g of relay ACR to close a point in the exit cycle start circuit in FIG. 6. Contacts h, i, j and k close points in the exit cycle select relay circuits, respectively, in FIGS. 7 and 8. Contact m of relay ACR closes a point in the energizing circuit of exit start unload relay ULRI in FIG. 12.

Pushbutton start switches PS2 and PS3 in FIG. 5 are pressed to start accumulator conveyors 34 and 38 running. Closure of start switch PS2 causes energization of contactor ZAM through stop switch SSZ across conductors L4 and L5. Contactor ZAM closes contacts a, b and c to connect three-phase power to motor M02 and thereby to start accumulator conveyor 34 running. Contact d of Contactor ZAM closes in shunt of start switch PS2 to maintain Contactor 2AM energized. In like manner, closure of start switch PS3 causes energization of Contactor 3AM through stop switch S83 across conductors L4 and L5. Contactor SAM closes contacts a, b and c to connect three-phase power to motor M03 and thereby to start accumulator conveyor 38 running. Contact d of contactor SAM closes in shunt of start switch PS3 to maintain Contactor SAM energized.

In FIG. 4, start switch PS5 is pressed to start intermediate conveyor 36 running. Closure of start switch PS5 causes energization of relay ICR through stop switch SSS across conductors L4 and L5. Relay ICR closes contact a in shunt of start switch PS5 to maintain relay ICR energized. Contact b of relay ICR closes an energizing circuit for Contactor IM through contact a of relay ILRI across conductors L4 and L5. Contactor IM closes contacts a, b and c to connect three-phase power to motor MO5 and thereby to start intermediate conveyor 36 running. Contact d of Contactor IM in FIG. 12 also closes to complete a point in the maintaining circuit for Contactor UM which controls unload transfer off conveyor motor M021.

In FIG. 4, master storage conveyor start switch PS6 is pressed to start all of the storage conveyors running. Closure of start switch PS6 causes energization of storage conveyors control relay SCCR through stop switch SS across conductors L4 and L5. Relay SCCR closes contact a in shunt of start switch PS6 to maintain relay SCCR energized. Contact b closes to complete parallel energizing circuits in FIGS. 4 and 5 for contactors ISM, 23M, IIPSM and LSM across conductors L4 and L5. The circuit for Contactor ISM extends through contact a of No. l storage conveyor stop controlled limit switch ILS6 and stop-reset switch SRI, The circuits for contactors ZSM, ISSM and LSM extend through similar contacts a of limit switches ZLS, IQLS and LLS and similar stop-reset switches SR2, SRI@ and SRL, respectively, associated with the other storage conveyors.

Contactor ISM closes contacts a, b and c to connect three-phase power to motor M06 and thereby to start storage conveyor No. 1 running. Similarly, contactors ZSM, 10SM and LSM each closes its contacts a, b and c to connect three-phase power to motors M07, M08 and M09 and thereby to start storage conveyors Nos. 2, l() and L, respectively, running.

In FIG. 6, the exit cycle is started by pressing pushbutton switch P827. Closure of switch P827 causes energization of exit cycle start relay XCSR through stop switches S527 and SSZS and contact g of automatic control relay ACR across conductors L4 and L5. Relay XCSR closes contact a thereof to complete a self-maintaining circuit in shunt of switch PS27 and contact g of relay ACR. Relay XCSR also closes contact b thereof to energize the primary winding of transformer PTS across conductors L4 and L5. Contact b of relay XCSR also connects conductor L4 to conductor L11 to energize the latter.

i The aforementioned energization of conductor L11 causes the photocell light source, that is, the lamp PCLZ in FIG. 6 to light. The light impinging on photocell PC2 causes energization of the latter to effect current flow from the rightahand end of the secondary winding of transformer PTS through unidirectional current conducting diode DRZ, resistors R3 and R4 and photocell PC2. to the left-hand of the secondary winding. The voltage drop across resistor R3 is applied to bias emitter E of transistor TR2 positive relative to base B thereof to render the transistor conducting, the latter being of the P-N-P conductivity type or the like. Current ows through emitter E and collector C of transistor TR2 and the operating coil of relay XPC to energize the latter and to close its contact a. As will be apparent, contact a closes a point in the energizing circuit of exit shuttle conveyor E@ power contactors XSI-I and XSL. Relay XX in FiG. 7 energizes in a circuit extending from conductor L11 through contact e of relay XSDB and contacts f and e of contactor XSI-1 and XSL to conductor LS and closes contact a and b thereof, the latter contact connecting power from conductor L11 through contact a ot relay XSLRA and contact f of relay XSLSA to conductor L12. I

Energization of conduct L12 causes energization of conductor L13 in FIG. 7 in a circuit extending from conductor L12 through exit cancel switch P831, contact b of relay XCCR., contacts c of relays X1LR, XZLR, XlilLR and XLLAR, contact c of relays XICR, contact b of relay XLRA and contact b of switch SA to co-nductor L13.

The aforementioned energization of conductor L12 effects energization of solenoids DN3, DN4, DNS and DN through contacts b of relays X1LR1, XZLRI, XLR1 and XLLR1, respectively, to cause stops ST3,

ST4, ST5 and ST6 or storage conveyors No. 1, 2, 10

and L, respectively, to be lowered. Relay XHTR iin FIG. 7 energizes in a circuit extending from conductor L4 through contact c of relay XLRA to conductor L5. Relay XHTR opens contacts a and c and closes contact b, contact a thereof being of the timed closing type as indicated by T.C. adjacent thereto and contact b being of the timed opening type as indicated by T.O. adjacent thereto. Relays X1CR1, X2CR1, X10CR1 and XLCR1 energize across conductors L11 and L5. As a result, contacts a of relays X1CR1, XZCRI, X10CR1 XLCRl in FIGS. 4 and S close to complete points in the energizing circuits of power contactors 18M, 28M, 10SM and LSM, respectively, of the storage conveyor motors. Relays XlCR, XZCR, XNCR and XLCR energize acrossV conductors L12 and L5 and close their contacts a in FIG. 6. The circuit for relay X1CR extends through limit switch 1LS9 in FIG. 9, Contact c of relay X1LR3 and contact d of relay X1LR2. The circuit for relay X2CR extends through limit switch 2LS9, contact c of relay XZLRS and contact d of relay XZLRZ. The circuit for relay XlliCR extends through limit switch 10LS9, contact c of relay XIQLRS and contact d of relay X10LR2. The circuit for relay XLCR extends through limit switch LLS9, contact c of relay XLLR3 and contact d of relay XLLRZ. Relay UCR in FIG. 12 energizes through contact b of limit switch ULSZ and contact c of relay ULR1 across conductors L11 and L5 and closes contact a in FIG. 6 in the circuit of the exit shuttle conveyor main contactors XSI-1 and XSL. k

The stored articles are accumulated against a stop on each storage conveyor. When a given storage conveyor is full, a counter locks out the operating circuit of its add coil so that it cannot be energized until such time as at least one article is withdrawn therefrom.

An operator at main operators station 2 withdraws articles from the storage conveyors to a production line through an outgoing conveyor 4t). This is done by pressing appropriate exit select pushbutton switches at the main operators station. Pressing anyV such exit select switch causes a space immediately on the left side of the space opposite storage conveyor No. L to be reserved for their article on exit shuttle conveyor 3i). The exit shuttle conveyor 3h then moves one space to position the reserved space opposite storage conveyor No. L and exit memory device XM1) moves one step to indicate and register the location of the rst selected article. When the reserved space on exit shuttle conveyor Siti reaches a point apposite the storage conveyor from which an article was seiected, an article is automatically moved into such reserved space on the exit shuttle conveyor by the corresponding exit transfer out conveyor 22, 2li, 26 or 2S.

As each additional article is reserved or marked for withdrawal, the aforedescribed operations are repeated and successive spaces are reserved. As a result, the articles are arranged on the exit shuttle conveyor in the order in which they are selected for movement through the outgoing conveyor. When the rst and each succeeding article reaches the exit end of shuttle conveyor 3h at least one space beyond transfer-out conveyor 22, unload transfer-off conveyor 32 is activated to move the article onto accumulator conveyor34. As the latter is running continuously, it moves the articles to an idling point at intermediate conveyor 36.

The function of accumulator conveyor 3S is to gather the articles received from the intermediate conveyor and thereby to eliminate any spaces therebetween. Accumulator conveyor 31S is provided with a counter which stops the intermediate conveyor when a predetermined number of articles have been accumulated and restarts the intermediate conveyor when this number is reduced. This action prevents pileups of articles at this location. The articles travel from accumulator conveyor 3S through outgoing conveyor 40 to a production line or the like.

The aforementioned functions will now be described in detail.

An article moving along storage conveyor No. 10, for example, engageslimit switch NLS@ in FIG. 10 to close the same and energize tripping coil T of relay XliDLRl through contact d of the latter. Relay X10LR1 closes Contact a to energize up-solenoid UPS and to raise stop STS. As a result, the article is stopped and stored on storage conveyor No. 10 although the latter runs continuously. Relay X10LR1 also opens its contact b to deenergize down solenoid DNS and permit the stop to be raised, closes contact c in the circuit of its closing coil C, opens its contact d to deenergize its tripping coil T and opens its contact e in the circuit of tripping coil T of relay XlilLRS. Opening of contact e of relay XltlLRl also prevents operation of closing coil C of relay X10LR2 thereby to prevent operation of transfer-out conveyor 26 until an exit selection has been made as hereinafter described.`

When the article engages stop ST5 on storage conveyor No. 10, it engages limit switch NLS? to close the same in FIG. l() to complete a point in the circuit of closing coil C of relay X1LR1. This closure of limit switch 10LS7 is indicative of the presence of at least one article on storage conveyor No. 10 and permits withdrawal of such article under the control of exit memory device XMD when an exit selection is made as hereinafter described. It will be apparent that unless an article is present on the storage conveyor and limit switch 10LS7 is closed thereby, exit transfer-out conveyor 26 cannot be started.

An article stored on storage conveyor No. 1 travels along storage conveyor No. 1 and engages and closes limit switch 1LSS in FIG. 9 to trip relay X1LR1 and raise stop ST3 at the exit end of the storage conveyor No, 1 and engages and closes limit switch 11.87 in FIG. 9 to prepare for release of articles from storage conveyor No. 1. Limit switch 1LS6 opens when stop ST3 is raised. In a similar manner, when articles are introduced onto the i3 Y other` storage conveyors, stops ST4, ST and ST6 are raised to hold the ,articles in storage until it is desired to withdraw articles therefrom. The system now remains in this condition with the articles resting against the stops at the exit ends of the storage conveyors until an exit selection 'is made to initiate withdrawal of an article therefrom as hereinafter described.

Exit Cycle Let it be assumed that at least one article has been stored on each storage conveyor and that it is desired to withdraw articles therefrom onto exit shuttle conveyor Si@ and then convey these articles along transfer-off conveyor 32, accumulator conveyor 34, intermediate conveyor 36 and accumulator conveyor 38 to outgoing conveyor 40 and along the latter to a production line or the like.

It will be recalled from the above description that storage conveyors Nos. 1, 2, and L have been started and run continuously. As a result, the articles stored on these conveyors rest against stops ST3, ST4, ST5 and ST6, respectively. The articles resting against these stops actuate limit switches 1LS7, 2LS7, 101.87 and LLS7 in FIGS. 9, 10 and l1 to close the same. These stops being in their raised positions, limit Vswitches ILS6, 2LS6, 10LS6 and LLS6 in FIGS. 9, 10 and 1l are open. It will also be recalled from the above description that accumulator conveyors 34 and 33 are running continuously and that intermediate conveyor 36 is running. Relays XlLRl, XZLRI, XlLRl and XLLRl are tripped and relays XILR3, XZLR, XlltlLR and XLLR3 are assumed to be initially in their closed conditions with their contacts in the positions shown. Relays XSLSA and ACR are energized.

When the exit cycle was started by pressing switch P827 in FIG. 6, relays XCSR, XPC, XX, XHTR, XICR, XZCR, XIGCR, XLCR, XICRI, X2CR1, XltiCRl, XLCRI and UCR energized. Relays XllLRl, XZLRI, XILRI and XLLRI were tripped as hereinbefore described when articles entered the respective storage conveyors. This caused energization of up solenoids UPS, UP4, UP5 and UF6 to maintain storage conveyor stops ST3, ST4, ST5 and ST6 in their raised positions.

Let it be assumed that it is desired to withdraw an article from storage conveyor No. l. For this purpose, select switch P832 is pressed. Pressing of exit select switch PS32 in FIG. 7 completes an energizing circuit from conductor L13 through switch XTC of counter CTR3, closing coil C of select relay XILR and contact h of relay ACR to conductor L5. Relay XILR closes its contact a in FIG. 6 to energize contactor XSI-I and relay XSTR, opens its contact b in FIG. 7 in the circuit of relay XICR, opens its contact c to disconnect power from conductor L13 thereby to lock out the select circuits and to deenergize its closing coil C, closes its contact d in FIG. 8 in the circuit of its tripping coil T and closes its contact e to energize solenoid 1S of exit memory device XMD. The circuit for contactor XSH extends from conductor L11 through contacts a of relays XILR, ALRI, XLCR, XIOCR, XZCR, XlCR, UCR, XLRA, XPC and XSDLR and contact d of contactor XSDB.

Energization of contactor XSH causes closure of its contacts a, b and c to connect high speed winding HSW of motor M016 to the three-phase source and to start exit shuttle conveyor 30 running at a high speed. Contacter XSH also opens its contact d to prevent energiza tion of dynamic braking contactor XSDB at this time, closes its contact e in FIG. 7 to energize relay XSI-IA and to complete a point in the circuit of closing coil C of relay XLR, and opens its contact f to deenergize relay XX.

Relay XSTR closes timed opening contact a, opens contact b and opens timed closing contact c in FIG. 7. Solenoid 1S in the lower portion of FIG. 8 upon being energized operates its actuator to prepare the same, when device XMD starts to rotate, to act upon pin P of actuator block AB at the left end, that is, in the Acolumn before column L of the lower row of actuator blocks to pivot the latter and thereby to prepare the same for closure of limit switch XILS when it engages the latter as hereinafter described. Relay XSHA closes its contact a in FIG. 6 to complete a maintaining circuit for contactor XSI-I to maintain the exit shuttle conveyor running. This circuit extends also through contact a of relay XSLSA in shunt of contacts a of relays XICR, XZCR, XIQCR and XLCR. Relay XSHA also closes its contact b in the manually operable exit shuttle index circuit in the upper portion of FIG. 7. Relay XX open its contact a in the circuit of tripping coil T of relay XLR and opens its contact b to lock out the select circuits by deenergizing conductors LIZ and L13.

Jhen exit shuttle conveyor 30 starts running, i-t disengages limit switch XSLS in FIG. 6 to complete a second maintaining circuit at its contact a for main contactor XSH through contacts a of relays XSCR, XSLR, XPC and XSDLR and contact d of contactor XSDB. Limit switch XSLS remains closed until the exit shuttle conveyor has moved one space whereupon limit switch XSLS is re-engaged to stop the exit shuttle conveyor. Contact b of limit switch XSLS in FIG. 7 opens to deenergize relay XSLSA.

Relay XSLSA opens its contact a in FIG. 6 to interrupt the rst mentioned maintaining circuit of contactor XSH, opens its contact b in the circuit of tripping coil T of relay XSDLR, opens its contact c to lock out the manual index circuit in FIG. 7, opens its contact'd to lockout relay XSCR, closes its contact e to energize closing coil C of relay XLR, opens its contact f to maintain the select circuits locked out, closes its contact g in FIG. 8 in the circuit of driving motor DMZ of exit memory device XMD, and opens its contact h in FIG. l1 to prevent energization of closing coil C of relay ALRl.

Relay XLR in FIG. 7 opens its contact a to deenergize its closing coil C, closes its contact b in the circuit of its tripping coil T and closes its contact c to energize relay XLRA. Relay XLRA opens its contact a in FIG. 6 in the original energizing circuit of contactor XSH, opens its contact b in FIG. 7 to maintain the select circuits deenergized, opens its contact c to deenergize relay XI-ITR, closes its contact d in FIG. 8 in the circuit of tripping coils T of select relays XILR, XZLR, XIOLR and XLLR, and closes its contact e in FIG. 8 in the circuit of drive motor DMZ of exit memory device XMD.

Relay XHTR closes its contact c in FIG. 8 to energize driving motor DMZ to rotate exit memory device XMD one step in the direction of the arrow. When exit memory device XMD starts to rotate, its limit switch XMDLS closes a maintaining circuit for its drive motor DMZ. Limit switch XMDLS maintains operation of drive motor DMZ until exit memory device XMD reaches its next operating position whereupon limit switch XMDLS is opened thereby to stop its rotation. After a predetermined time interval suicient for limit switch XMDLS to have closed the aforementioned maintaining circuit, timed opening contact b of relay XHT R opens to interrupt the original energizing circuit of drive motor DMZ. When drive motor DMZ starts to rotate exit memory device XMD, its switch a is opened to prevent tripping of select relay XlLR and remains open until the memory device reaches its neXt operating position. When exit memory device XMD starts to rotate, pin P of the first actuator block AB in the rst column thereof engages the actuator member of solenoid 1S to pivot or set the actuator block counterclocltwise into its angular position. After the aforementioned time interval, timed closing contact a of relay XHTR closes. It will be apparent that contacts b and c of timing Vrelay XHTR initiate operation of the exit memory device. Contact a of relay XHTR prevents tripping of the closed select relay until exit memory device and XMD starts rotating. When the exit memory device reaches its operating position 2, switch a recloses to and 8, its contact e interrupting energization of solenoid Y lS of exit memory device XMD.

The aforementioned pivoting of the actuator block of exit memory device XMD constituted a reservation of a space on the exit shuttle conveyor for an article to be received from storage conveyor No. l. The space that is reserved each time a select switch is pressed Iis the space that is opposite storage conveyor No. L after the exit shuttle conveyor has moved one space. When a sucient number of selections have been made so that this reserved space reaches the selected storage conveyor, an article Vis withdrawn therefrom onto the exit shuttle conveyor in the manner hereinafter described.

When eXit shuttle conveyor approaches the end of its one-space movement, it engages limit switch XSDLS at the upper left-hand portion of FIG. 7 to close the same. As a result, closing coil C of relay XSDLR is energized through contact c of the lat-ter. Relay XSDLR opens its contact a to deenergize contactor XSH and closes its contact b to energize contactor XSL. As a result, high speed winding HSW is disconnected and low speed winding LSW of motor'MOl6 is connected to the three-,phase source to reduce the speed of exit shuttle conveyor 3h. Relay XSDLR also opens contact c to deenergize its closing coil C, closes contact d in the circuit of its tripping coil T and closes contact e in the circuit of relay XSCR. Exit shuttle conveyor 3@ then reengages limit switch XSLS to open contact a and to close Contact b of the latter. Contact a of limit switch XSLS deenergizes contactor XSL and relay XSTR and contact b thereof energizes relay XSLSA. Contacter XSL restores its contacts to the positions shown in FGS. 6 and 7.

Relay XSTR closes its Contact b to energize dynamic braking contactor XSDB through contacta of relay XSTR and contacts d of contactors XSH and XSL.

Contactor XSDB closes its contacts c, b and c to connect direct current to low speed windings LSW of motor M016 to dynamically brake the motor and to stop the exit shuttle conveyor. Contactor XSDB also opens its contact d to prevent energization of contactors XSH and XSL and opens its contact e to prevent energization of relay XX.

Relay XSTR opens its contact a after a predetermined time interval suicient to allow stopping of motor M016 under dynamic braking thereby to deenergize contactor XSDB and restore its contacts to the positions shown. Contact e of contactor XSDB energizes relay XX through contacts f and e of contactors XSH and XSL, respectively. Relay XX closes Contact a to energize tripping coil T of relay XLR in a circuit extending through contact b of the latter, contacts c of select relays XlLR, XZLR, XMiLR Yand XLLR, Contact b of relay XCCR and cancel switch P531. Relay XLR at contact c deenergizes relay XLRA to cause the contacts of the latter to restore to the positions shown in FIGS. 6 and 7.

The aforementioned energization of relay XSLSA causes closure of its contact a in FIG. 6, closure of its contact b in the circuit of tripping coil T of relay XSDLR, closure of its contact c, closure of its Contact d to energize relay XSCR, opening of its contact e, closure of its contact f and opening of its contact g in FlG. 8.

Relay XSCR opens its contact a in FIG. 6, closes its contact b in the circuit of closing coil C of relay XSLR, and closes its Contact c in shunt of Contact d of relay XSLSA to maintain itself energized. A predetermined time interval after deenergization of relay XSTR as aforedescribed, contact c thereof closes to energize tripping coil T of relay XSDLR. Relay XSDLR restores its contacts to the positions shown, its contact e deenergizing relay XSCR.

It will be apparent that relay XSCR was energized and deenergized without ellect as described above. Relay XSCR is provided to control the system in the event the exit shuttle conveyor overrides limit switch XSLS as agrar 16 hereinafter described. it limit switch XSLS is overriden, relay XSDLR will not trip because Contact b or^ relay XSLSA reopens. Closing coil C of relay XSLR in FG. 6 will energize through contact a of limit switch XSLS, contact b of relay XSCR and contact b of relay XSLR. Contact d of relay XSLR will energize relay XSLRA. Relay XSLR will open Contact a to stop the exit shuttle conveyor, open contact b to deenergize its closing coil C and close contact c in the circuit of its tripping coil T. Relay XSLRA will open its contact a to lock out the closing coils Cot the select relays by deenergizing conductors L12 and LES, open its contact b in FIG. 8 to lock out tripping coils T of the select relays and open its contact c in FlG. 8 to lock out drive motor DMZ of the exitrmemory device. This will prevent operation or" the system until the exit shuttle conveyor is repositioned to its proper position causing actuation of limit switch XSLS.

The system operates in the manner hereinbefore described each time a select switch is pressed. That is, the exit memory device is operated to reserve a space on the exit shuttle conveyor and the exit shuttle conveyor is operated to move one space in the right-hand direction as seen in FIG. l. n

When sullicient selections have been made so that the space reserved on the exit shuttle conveyor for an article to be withdrawn from storage conveyor No. l reaches a point directly opposite the latter, exit memory device XMD will also have been rotated or stepped in unison with the exit shuttle conveyor movements to a position wherein the pivoted actuator block AB in the lower row thereof engages and closes limit switch XlLS in FIG. 8. Limit switch lLS' in FIG. 9 having been closed by au article resting against stop ST3, closing coil C of relay XlLRl is energized in a circuit extending from conductor Ll?. in FG. 8 through limit switches XlLS, lLS' and llLSltl, a Contact a of relay XllLRZ in FIG. 9, contact c of relay XllLRlt and closing coil C to line L5.

Relay XlLRl opens contact a to deenergize up solenoid UPS and closes contact b to energize down solenoid DNS to lower stop ST3 of storage conveyor No. l to release an article from the latter. Relay XllLRl also opens contact c to deenergize its closing coil C, closes contact d in the circuit ot its tripping coil T and closes its contact e in the circuit of closing coil C of relay XlLRZ.

When stop ST3 reaches its lower position, it engages and closes limit switch lLS6 in FIG. 9, to energize closing coil C of relay XLLRZ in a circuit extending from limit switch lLSlt? through Contact e of relay XLRll and contact b of relay XlLR2. As storage conveyor No. l runs continuously, lowering of the stop also causes an article to be moved onto exit transfer out conveyor 2.2. Closure of limit switch llLS6 also causes energization of tripping coil T of relay XLRS through Contact b of the latter, contact b of relay lLSltbA and Contact e of relay XlLRll to limit switch 1LS6. Limit switch lLS'l opens.

Relay XlLRZ opens Contact a in the circuit of closing coil C of relay XlLRI'l, opens contact b to deenergize its closing coil C, closes contact c in the circuit of its tripping coil T, opens contact d to dcenergize relay XlCR and closes Contact e to energize main contactor XlM across conductors LllZ and L5. Relay XlLRS closes Contact a in the circuit of its closing coil C, opens contact b to deenergize its tripping coil T and opens Contact c in the circuit of relay XlCR.

Relay XlCR opens its contact a in FIG. 6 to lock out and prevent operation of exit shuttle conveyor Sli. Contacter XItM closes its contacts a, b and c to connect motor M017 to the three-phase power supply source to start exit transfer-out conveyor 22 running. When exit transfer-out conveyor 22 starts moving, it disengages limit switch ILSS to cause the latter to close and complete a maintaining circuit for contactor XTM. When the ram fof transfer-out conveyor 22 moves the article over exit shuttle conveyor 30, it engages limit switch 1LS9 to close contact a thereof in FIG. 7 and to open contact b thereof in FIG. 9. Contact a of limit switch 1LS9 energizes subtract coil S of counter CTRS at the lower righthand portion of FIG. 5, the circuit therefore extending through contact b of pushbutton switch P536, and the conductor extending along the right-hand sides of FIGS. through 8. As a result, counter CTR3 is stepped one step in the counterclockwise direction to register the withdrawal of one article from storage conveyor No. 1. Contact b of limit switch 1LS9 in FIG. 9 maintains relay XICR deenergized. Contact a of limit switch 1LS9 also energizes tripping coil T of relay X1LR2 through contact c of the latter. Relay X1LR2 closes contacts a, b and d and opens contacts c and e.

As storage conveyor No.l 1 moves the article onto exit transfer-out conveyor 22, the next article engages limit switch ILSS in FIG. 9 to energize tripping coil T of relay X1LR1 through contact d of the latter. Relay `XILRI opens contact b to deenergize down solenoid DNS and closes contact a to energize up solenoid UP3 to raise stop No. 1 and to stop the next article. Relay XILRI also closes contact c and opens contacts d and e. Raising of the stop causes limit switch 1LS6 to reopen.

When the first article reaches its position on exit shuttle conveyor 30, it engages limit switch lLSl in FIG. 9 to open contacta and to close contact b thereof. Contact a of limit switch 1LS10 prevents operation of closing coil C of relay X1LR1 and contact b thereof energizes relay lLSlA. Relay 1LS10A closes contact a to energize closing coil C of relay XILRS, opens contact b in the circuit of tripping coil T of relay XILRS and closes contact c in FIG. l2 in the circuit of closing coil C of relay ALRZ. Relay X1LR3 opens contact a to deenergize its closing coil C, closes contact b in the circuit of its tripping coil T, closes contact c to energize relay X1CR, closes its contact d in FIG. 12 and opens its contact e. Relay XICR closes its contact a in FIG. 6 to prepare the exit shuttle conveyor for operation.

When transfer-out conveyor 22 has completed its cycle of operation, it reengages limit switch 1LS5 to open the same and to deenergize contactor X1M. As a result, motor M017 is disconnected from the power supply source to stop transfer-out conveyor 22.

When another exit selection has been made causing -movement of exit shuttle conveyor 30 one space in the right-hand direction and movement of such rst article to the right-hand end of the exit shuttle conveyor into registration with unload transfer off conveyor 32 as shown in FIG. 1, the article that was withdrawn from storage conveyor No. l engages limit switch ULS2 in FIG. 12 to close contact a and to opencontact b thereof. Contact a of limit switch ULSZ energizes closing coil C of relay ULR1 through contact m of relay ACR, contact a of relay ULRZ and contact a of relay ULR1.

`d of intermediate conveyor motor main contactor IM.

Contacter iUM closes contact a in its maintaining circuit and closes contacts b, c and d to connect motor M021 to' the three-phase power supply source thereby to start transfer-011 conveyor 32 running.

When transfer-oli conveyor 32 starts moving, it disengages limit. switch ULSI in FIG. 12 to cause closure thereof and to complete a maintaining circuit for Vcontactor UM through contact a of the latter and then in 18 parallel through contact d of relay ULR3 and contact d of contactor IM. Limit switch ULSl maintains contactor UM energized until the transfer-olf conveyor has completed its cycle of operation and reengages limit switch ULSI to open the same and deenergize contactor UM to stop the transfer-cfr conveyor.

When the article moves along transfer-off conveyor 32,

'it engages limit switch ULS3 in FIG. 12 to energize closing coil C of relay ULR2. Relay ULRZ opens contact a in the circuit of closing coil C of relay ULRl, closes contact b to energize tripping coil T of relay ULRl through contact b of the latter and limit switch ULS3, opens contact c to deenergize its closing coil C, closes contact d in the circuit of its tripping coil T, opens contact e to interrupt the original energizing circuit of contactor UM and closes contact f in shunt of contacts d of relay ULR3 and contactor IM, respectively. Limit switch ULS2 is disengaged to open contact a and to close contact b thereof.

Accumulator conveyor 34 runs continuously and moves the article from unload transfer-olf conveyor 32 toward intermediate conveyor 36. The article engages limit switch iULS4` to energize closing coil C of relay ULR3 through contact b of the latter. Relay ULR3 closes contact a to energize tripping coil T of relay ULRZ through contact d of the latter and limit switch ULS4, opens contact b to deenergize its closing coil C, closes contact c in the circuit of its tripping coil T and opens contact d in the original energizing circuit of contactor UM. Relay ULR2 restores its contacts to the positions shown in FIG. 12.

The article travels from accumulator conveyor 34 over the aforementioned idle portion onto intermediate conveyor 36 and closes and reopens limit switch ULSS to trip relay ULRS. Also, when unload transfer-off conveyor 32 has completed its cycle of operation and returns to its normal position, it reengages limit switch USLl to open the same. As a resclt, limit switch ULSl deenergizes contactor UM to stop the unload transfer-olf conveyor. Contact d of contactor IM maintains contactor UM energized until relay ULR2 is tripping and relay ULR3 is closing.

If exit select switch P833 at the lower portion of FIG. 7 is pressed, the system operates in the manner hereinbefore described except that the circuit elements associated with storage conveyor No. 2 operate instead of the circuit elements associatedwith storage conveyor No. l. For example, solenoid 2S of exit memory device XMD in FIG. 8 pivots the actuator block AB then adjacent the solenoid to reserve a space on exit shuttle conveyor 30. And when suicient selections have been made, the article is released from storage conveyor No. 2 and moved onto the exit shuttle conveyor under the control of the circuit shown in the lower portion of FIG. 9 and the upper portion of FIG. 10.

The system operates in a similar manner when switches P834 and P835 at the upper portion of FIG. 8 are pressed to Withdraw articles from storage conveyors Nos. 10y and L. In each case, the exit shuttle conveyor moves one` space in the right-hand direction as shown in FIG. l and exit memory device XMD is stepped once to retain a memory of the reserved space.

Select All If it is desired to selet an article from all of lthe storage conveyors, select all switch SA, portions of which are shown in FIGS. 6, 7 and 11, is turned from its SINGLE operating position to its ALL operating position wherein contacts a and c arekclosed and contacts b and d are opened. As a result, contactorXSH is energized in a circuit extending from conductor L11 in FIG. 6 through contact a of switch SA, contact a of relay ALRI, contacts a of relays XLCR, XICR, XZCR, XICR, UCR, -XLRA, XPC and XSDLR and contact d, of contactor SXDB to conductor L5. `This causes operation of exit shuttle 

1. IN A CONVEYOR SYSTEM HAVING A BUFFER STORAGE AREA INCLUDING A PLURALITY OF STORAGE CONVEYORS FOR STORING ARTICLES THAT ARE IN TRANSIT BETWEEN AN INCOMING CONVEYOR AND AN OUTGOING CONVEYOR; MEANS FOR WITHDRAWING ARTICLES FROM SELECTED STORAGE CONVEYORS TO THE OUTGOING CONVEYOR COMPRISING: AN INTERMITTENTLY OPERABLE EXIT CONVEYOR EXTENDING PAST THE EXIT ENDS OF THE STORAGE CONVEYORS AND HAVING ARTICLE RECEIVING SPACES THEREALONG AND BEING EFFECTIVE IN RESPONSE TO EACH OPERATION THEREOF TO MOVE ONE INCREMENT: THE EXIT ENDS OF THE STORAGE CONVEYORS BEING SPACED APART ACCORDING TO WHOLE NUMBER MULTIPLES OF SAID INCREMENTS SO THAT SAID EXIT CONVEYOR BETWEEN MOVEMENTS THEREOF STOPS SAID ARTICLE RECEIVING SPACES THEREON IN REGISTRATION WITH THE STORAGE CONVEYORS; A PLURALITY OF SELECTIVELY OPERABLE EXIT CONTROL DEVICES FOR INITIATING WITHDRAWAL OF ARTICLES AND BEING OPERABLE TO ESTABLISH THE STORAGE CONVEYOR ORIGINS OF SUCCESSIVE ARTICLES IN ACCORDANCE THEREWITH; AND ARTICLE WITHDRAWAL CONTROL MEANS CONTROLLABLE BY SAID EXIT CONTROL DEVICES COMPRISING 